* g10/trustdb.c (init_trustdb): Recognize tofu and tofu+pgp as
possibly saved trust models. Also register the ultimately trusted
keys if the trust model is tofu or tofu+pgp.
(check_trustdb): Don't skip if the trust model is tofu or tofu+pgp.
(update_trustdb): Likewise.
(tdb_check_trustdb_stale): Likewise.
(validate_keys): If the trust model is TOFU, just write out the
ultimately trusted keys.